1. Field of the Invention
The present invention relates to a method for controlling a compressor in an air conditioner, and more particularly to a method for controlling a compressor in an air conditioner so as to reduce the difference between discharge pressure and suction pressure in the compressor.
2. Description of Prior Art
Referring to FIG. 1 , there is shown an example of conventional air conditioners. In the air conditioner, room temperature is sensed by a room temperature sensor 10; an outdoor heat exchanger temperature is sensed by a temperature sensor 1'; an indoor heat exchanger temperature is sensed by a temperature sensor 2'. An invertor 8 controls amount of circulating refrigerant through a compressor 5 to reverse the operation of compressor 5 from the cooling mode to the heating mode, or vice versa. At this time, invertor 8 outputs as high a frequency voltage as possible, in order to shorten the operation mode reversal time in each reversal of the operation mode. Thus, high speed rotation of compressor 5 could be possible, thereby reducing operation mode reversal times for cooling, heating and defrosting operations.
However, although reducing the operation mode reversal time, the high speed rotation of compressor 5 resulted from the above-mentioned high frequency voltage outputted from invertor 8 causes a considerably high pressure difference between discharge pressure and suction pressure in the compressor. As a result, refrigerant of high pressure returns to compressor 5, thereby generating high pressure noise. If such high pressure refrigerant flows into compressor 5 at this time, the compressor may be damaged.
A representative example of attempts to solve the above-mentioned problems is disclosed in Japanese Patent Laid-open Publication No. 57-150763. A heat exchanger temperature sensor and a room temperature sensor sense heat exchanger temperature and room temperature and supply signals corresponding to the sensed temperatures to a temperature control circuit, respectively. When a difference between the two temperatures is no more than a predetermined value the temperature control circuit applies a signal to a switch for a compressor drive circuit, which switch then turns on. A first timer which is connected to the switch in series via a contact of a second relay produces conducting time. As the first timer counts a predetermined time, a first timer switch turns on, so that the second relay connected to the first timer switch in series via a second timer switch can conduct. Conducting of the second relay makes the other contact of second relay turn off, so that the contact of first relay turns off, thereby causing the compressor connected thereto in series to stop. Such conventional device thus involves stopping the compressor for a predetermined time before the reversal of operation mode .